Astronomy Test 3: Suns effects CH15

Differential rotation

rotation rate of the plasma varies with solar latitude

Why do scientists want to understand the relationship between active regions, changes in the magnetic field, and large-scale eruptions?

so they can better predict "storms" and their consequence on Earth

Heliosphere

where the solar wind is slowed and stopped by interstellar wind

Active region studied at different heights in the Solar atmosphere

- Loops of material in corona - Light emitted from regions where flares start - Light emitted by active regions in corona - Magnetic polarity of sunspot: Black = magnetism pointing in towards sun's core, White = magnetism pointing out towards us

Sun's Complex magnetic field

- Magnetic field lines of the Sun wind up and form loops due to the Sun's differential rotation - some of these magnetic lines are closed and others open

Effects of Solar weather on Earth

- Northern & Southern lights - Solar flare effects can reach Earth in tens of minutes, but the effects of CMEs can take several days to reach the planet -> bring x-rays, energetic particles, and intense UV radiation to Earth's atmosphere - X-rays and UV photons can ionize atoms in Earth's atmosphere thus freeing electrons which can build up on spacecraft when charge dissipates, the spacecraft electronics can be damaged - Earth's ionosphere (part of atmosphere) can also be heated and become inflated causes extra drag on satellites pulling them into lower orbits; also distorts radio signals sent by spacecraft - Earth's magnetic field become distorted and induces electrical currents that can create surges in power lines - Higher levels of radiation for astronauts during solar storms

Model of Sun's magnetic field

- Spectral lines are created by electrons absorbing or emitting photons of light. These spectral lines can be split by the presence of a magnetic field - known as the Zeeman effect - The Sun's "sphere of influence" is determined by the reach of its magnetic field - Heliosphere - where the solar wind is slowed and stopped by interstellar wind

Describe the fate of Earth

- Sun's increasing radius will vaporize Earth or potentially lose its gravitational pull on the planet sending it out in the unknown - Long before the radius increases, however, the Sun will be too hot for life to exist

Solar Cycle

- The Sun's magnetic field changes every 11 years, which affects the number of active regions - Most easily tracked through how many sunspots appear on the Sun's surface - Sunspots often occur in pairs linked by magnetic field line Gas of chromosphere becomes trapped along the field lines Solar prominence + Filaments - Coronal holes and the Solar wind

If you were concerned about space weather and wanted to avoid it, where would be the safest place on Earth for you to live?

- Equator (farthest away from weak points, the poles) - Underground (farther from radiation)

plage

a bright region of the solar surface observed in the light of some spectral line

prominence

a large, bright, gaseous feature that appears above the surface of the Sun and extends into the corona

coronal mass ejection (CME)

a solar flare in which immense quantities of coronal material—mainly protons and electrons—is ejected at high speeds (500-1000 kilometers per second) into interplanetary space

solar flare

a sudden and temporary outburst of electromagnetic radiation from an extended region of the Sun's surface

active region

an area on the Sun where magnetic fields are concentrated; sunspots, prominences, flares, and CMEs all tend to occur in active regions

How can the prominences, which are so big and "float" in the corona, stay gravitationally attached to the Sun while flares can escape?

They must be traveling at a fast enough speed to escape the gravitational pull of the sun

Solar Dynamo

converting kinetic energy into electricity

Suppose an (extremely hypothetical) elongated sunspot forms that extends from latitude of 30 degrees to latitude of 40 degrees along a fixed longitude on the Sun. How will the appearance of that sunspot change as the Sun rotates?

one part of the sunspots will be moving faster, so it will begin to tilt and eventually it may break up into two or more sunspots